JPH06269858A - Bending machine - Google Patents

Abstract

PURPOSE:To provide a bending machine by which closing bend is performed easily and precisely without being influenced by the deflection of a work. CONSTITUTION:Bending is performed by rollingly pressing a revolving roller 18 on a work W which is held between a press die 13 and a fixed die 15 and by bending the work W along the surface 13a to be bent. For obtaining a bent part of a closing shape, the upper side that is already bent is held by a vacuum pad 27 and raised upward at the time of bending the final side, and the bending is performed in such state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending machine for bending a plate material in a plurality of times to obtain a bending product having a closed cross section.

[0002]

2. Description of the Related Art A bending process for obtaining a polygonal cylindrical body 101 having a closed cross section as shown in FIG. 7 by bending a plate material such as a relatively thin steel plate a plurality of times is generally a closing bending (or a bag bending). )It is called.

Conventionally, in such closing bending, the closing cross section is relatively small (one side is 50 to 50).
In the case of a processed product of about 100 mm), bending is performed by a press or a press brake using a mold having a special shape or a mold with a cam. In that case, in order to improve the product accuracy, a core is put in the closing part for processing.

On the other hand, in the case of a processed product having a relatively large cross-section (one side is about 500 to 1000 mm), it is difficult to use a method such as the above-described processed product having a small cross section. As shown in FIG. 8, a bending process is performed so that the cutout 102 remains in a part of the cross section, and another plate 103 is attached to the cutout 102 by welding or the like. A method of forming two members 104, 104 having a U-shaped cross section as shown by bending and joining opposing edges of these members 104, 104 by welding to obtain a desired closing shape is known. It is used. The former method (FIG. 8) is used for products such as refrigerators and washing machines, and the latter method (FIG. 9) is used for products such as fuel tanks.

However, in each of the above-mentioned methods used for a relatively large cross-section processed product, two parts are required.
Since it is divided into two parts, welded parts are necessary, liquid leakage may occur from these welded parts, the appearance quality is poor, and cost increase is inevitable. Note that, in such a processed product, it is possible to perform R-bending using a press brake as shown in FIG. 10, but in such a case, the punch 105 is formed at the time of bending as shown in the drawing. Since it interferes with the work 106, it is impossible to perform overvent,
There is a problem that the finished product has a mouth-opening state and the shape needs to be adjusted by reworking, which complicates the working process.

Therefore, in order to solve these various problems and obtain a product with a perfect closing shape from a single plate material, a closing bending method using a so-called bending machine has been proposed. This bending machine is
A pressing die having a peripheral surface having a predetermined radius, a fixed die arranged below the pressing die and sandwiching and fixing a work between the pressing die, and a peripheral surface of the pressing die. A bending die that moves in an arc shape along the holding die and a fixed die, and the workpiece is sandwiched between the holding die and the holding die to move the bending die in an arc along the peripheral surface of the holding die. The work can be bent to a required bending radius.

Next, a closing bending process using this bending machine will be described with reference to FIG.
First, a work 1 to be bent as shown in (a).
The rear edge of 07 is brought into contact with an NC controlled stopper (hereinafter referred to as NC stopper) 108, and the workpiece 107
The front end portion of the work 107 is bent in a state where is positioned. Then, as shown in (b) and (c), N
By controlling the C stopper 108 to the forward position, the front end of the work 107 is sequentially bent. Finally, as shown in (d), the work 107 is once taken out of the apparatus and
After the direction is changed by 80 ° and the front end edge of the work 107 is brought into contact with and positioned by the manual stopper 109, the front end of the work 107 is bent to obtain the final product. In FIG. 11, the two-dot chain line indicates the position of the work 107 where bending is actually performed, and the solid line indicates the position where the work 107 is returned by spring back after bending. Is.

[0008]

By the way, when the closing bending is performed using the bending machine as described above, the bending of the final side 107a of the work 107 as shown in FIG. 12 ((d in FIG. 11) is performed. ) Step) when the upper side 1
In some cases, 07b and the side edge 107c that was first bent were bent by its own weight from the two-dot chain line position to the solid line position. When the upper side 107b and the side side 107c bend in this manner, the end of the upper side 107b moves downward by δ ₁ ,
When bending the final side 107a, the upper end of the final side 107a and the lower end of the side 107c overlap by δ ₂ so that they cannot be bent. If this bending is forced, the side 107c is also bent. As a result, normal bending cannot be performed.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a bending machine capable of easily and accurately performing closing bending without being affected by the bending of a work. To aim.

[0010]

A bending machine according to the present invention comprises: (a) a fixed mold fixed on a mount,
(B) A holding die which has a bending surface formed of an arcuate surface with a predetermined radius on one side and which can move up and down to sandwich a plate-like work with the fixed die, (c) a bending center of the bending surface A bending beam that is swingably supported on the gantry about a point on the line of movement, and (d) is rotatably supported by the bending beam, and moves around the bending center as the bending beam swings. By doing so, a rotary roller that is pressed onto the work sandwiched between the fixed mold and the pressing mold, and (e) a plurality of bending-worked products of the work to obtain a closing-shaped bent product having a closed cross section. At this time, the work holding means is provided to hold and raise the already bent side at the time of bending the final side to prevent interference between the sides.

A position for holding the work until the bending beam starts the swinging operation after the work is sandwiched between the fixed mold and the pressing mold to prevent the work from being displaced. It is preferable to provide deviation prevention means.

Further, it is preferable to provide a positioning stopper which abuts on an end edge of the work at the time of bending the work so as to define a bending leg length of the work. It is preferable that the positioning stoppers are provided before and after the work carrying-in direction.

[0013]

When the work is placed at a predetermined position on the fixed mold, the pressing mold is lowered, and the work is sandwiched and fixed between the fixed mold and the pressing mold. In this state, the bending beam is swung in an arc shape around the bending center of the bending surface, and accordingly, the rotating roller is moved in an arc shape around the bending center of the bending surface. In this way, the work is pressed by the rotating roller against the bending surface of the pressing die and bent at a predetermined bending radius. Then, a bending-shaped product having a closing shape is obtained by sequentially shifting the bending position and bending the work a plurality of times. At the time of this closing bending, when the final side is bent, the side that has already been bent is held and raised by the work holding means, and interference due to the bending of the work between the final side and the side adjacent above it is thereby caused. Avoided and easy and accurate closing bending.

Further, when the positional deviation prevention means is provided, the workpiece sandwiched between the fixed die and the pressing die is held by the positional deviation prevention means until the start of the bending operation. It is possible to prevent the bending process with higher accuracy.

Further, when the positioning stopper is provided, the bending stopper position of the work is easily set by the contact of the positioning stopper with the edge of the work.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of the bending machine according to the present invention will be described with reference to the drawings.

FIG. 1 shows the entire construction of a bending machine according to an embodiment of the present invention, and FIG. 2 shows a front view of a bending mechanism section. The bending machine according to the present embodiment hits a bending mechanism section 1, a wheel conveyor 2 that carries a work into the bending mechanism section 1, and a rear end edge of a workpiece that is provided below the wheel conveyor 2 and is in a bending position. A first work positioning stopper 3 for positioning the work by contacting it, and a front end of the work at the bending position, which is provided at a position facing the first work positioning stopper 3 with the bending mechanism portion 1 interposed therebetween. A second work positioning stopper 4 for positioning the work by contacting the edge is provided.

In the bending mechanism section 1, a gate type frame 6 is erected on a frame 5. A linear guide 6a is provided on the inner side surface of the gate frame 6, and the base end of the plate pressing beam 7 is moved up and down by the operation of the pressing cylinder 8 along the linear guide 6a. Further, the plate pressing beam 7 is extended in a direction traversing the wheel conveyor 2, and a roller follower 9 (see FIG. 3) is attached to the tip thereof. This roller follower 9 is a U-shaped groove 10a of a guide plate 10 provided below at the lower limit position of the plate pressing beam 7.
It is fitted inside, and in this fitted state, the clamp cylinder 11 is actuated to be pressed downward for positioning by the plate pressing beam clamp 12 whose lower surface is the wedge surface 12a.

Further, as shown in FIG. 5, at the lower end of the plate pressing beam 7, a pressing die 13 having a bending surface 13a forming an arc of a constant bending radius R is attached to one side. By pressing the work W along the bending surface 13a of the pressing die 13, the work W is bent at the bending radius R.

On the other hand, below the pressing mold 13, a fixed mold 15 is fixed on the frame 5 via a shim 14, and the fixed mold 15 is pressed by changing the plate thickness of the shim 14. The height can be adjusted along the moving direction of the mold 13.

A bending beam 16 is arranged in front of the fixed mold 15 (to the left in FIG. 5). The bending beam 16 includes beam edges 16a, 16 provided at both edges.
a and a block 16b interposed between the beam edges 16a and 16a, and the upper ends of both beam edges 16a and 16a are attached to the mount 5.
7 (see FIG. 2) so that it can be rocked, this bending beam 16 thereby allows the bending surface 13a of the holding die 13 to be bent.
It is possible to swing along. Where bending beam 1
The swing center of 6 is located on the moving line (vertical line) of the bending center 13b of the bending surface 13a, and in the actual bending process, the pressing die 13 is aligned so that the bending center 13b coincides with the swing center. The lower limit position, that is, the height of the fixed mold 15 is adjusted.

Further, both beam edges 1 of the bending beam 16 are
A rotary roller 18 is rotatably supported between 6a and 16a. As shown in FIG. 2, the rotating roller 18 is supported through elongated holes 16c formed in each beam edge 16a, and the position of the rotating roller 18 in the elongated holes 16c is adjusted by an adjusting screw. The distance between the rotary roller 18 and the center of swinging of the bending beam 16 is adjusted by the adjustment by 19.

At the lower end of the bending beam 16, a pedestal 5 is installed.
The tip of the rod of the bending cylinder 20, which is swingably supported by the, is pivotally supported. When the bending cylinder 20 is actuated, the bending beam 16 is swung in the direction of arrow P from the solid line position to the two-dot chain line position in FIG. 5 around the bending center 13b, and the rotating roller 18 is similarly bent at the bending center. It is swung about 13b.

On the front surface of the block 16b of the bending beam 16, three first work holding devices 21 are provided at positions near the gate frame 6 as position deviation preventing means. The first work holding device 21 has a vertical movement cylinder 22 and a vacuum pad 23 attached to the tip of the rod of the vertical movement cylinder 22, and when the work W is positioned on the fixed mold 15. Each vacuum pad 23 holds the work W until it is actuated to start the bending operation, thereby preventing the work W from being displaced.

A supporting beam 24 is cantilevered in the same direction as the extending direction of the plate pressing beam 7 above the plate pressing beam 7 in the substantially central portion of the gate frame 6 (see FIG. 2). ), The support beam 24 is provided with two second work holding devices 25. The second work holding device 25 has a vertical movement cylinder 26, a vacuum pad 27 attached to the tip of the rod of the vertical movement cylinder 26, and a guide bar 28 for guiding the vertical movement of these vacuum pads 27. , It serves to hold and raise the already bent side when bending the final side of the work W in the closing bending process. Although not shown in the drawing, three limit switches are attached to the movable member of the vertical movement cylinder 26, and three dogs are attached to the guide bar 28 (fixed member). The vertical movement cylinder 26 is controlled so that the vacuum pad 27 stops at the upper limit position, the lower limit position and the work holding position when the switch contacts the corresponding dog.

Next, the first work positioning stopper 3 will be described with reference to FIG. The first work positioning stopper 3 is NC-controlled,
The stopper main body 30 supported so as to be movable in the loading direction of the work W along the guide rail 29 provided above, the vertical movement cylinder 31 attached to the upper portion of the stopper main body 30, and the rod of the vertical movement cylinder 31. And a workpiece contact body 32 attached to the tip. On the other hand, a ball screw 33 is arranged on the gantry 5 in the same direction as the guide rail 29. Both ends of the ball screw 33 are supported by bearings 34, 34, and the ball screw 33 is driven to rotate by a servo motor 35 provided at one end side via a coupling 36. A moving body 37 fixed to the stopper body 30 is screwed into the ball screw 33, and when the servo motor 35 is rotationally driven by this, the stopper body 3 is moved.
0 is moved between the solid line position and the two-dot chain line position in FIG.
In addition, the work contact body 32 is moved to the protruding position (shown by a chain double-dashed line) above the wheel conveyor 2 by operating the vertical movement cylinder 31 at a predetermined stop position.

Since the second work positioning stopper 4 has substantially the same structure as the first work positioning stopper 3, the detailed description thereof will be omitted.

Next, the bending operation of the work W performed by using the bending machine configured as described above will be described with reference to FIGS. 5 and 6. First, the height of the fixed mold 15 and the position of the rotary roller 18 are adjusted according to the plate thickness of the work W to be processed and the bending radius R of the pressing mold 13 prior to the bending process. That is, the shim 14 is adjusted so that the swing center of the bending beam 16 coincides with the bending center 13b of the holding die 13 in a state where the work W is sandwiched between the holding die 13 and the fixed die 15. While adjusting the height of the fixed mold 15, the adjusting screw 19 (see FIG.
By moving the rotary roller 18 according to the above), the axial distance between the center of rotation of the rotary roller 18 and the swing center of the bending beam 16 is adjusted, so that the upper end of the rotary roller 18 is fixed to the fixed mold 15. Match the top surface.

Next, the work W is carried into the bending mechanism 1 by the wheel conveyor 2 while the pressing cylinder 8 is operated and the pressing die 13 is retracted upward. The first work positioning stopper 3 (see FIGS. 1 and 4) is retracted below the upper surface of the wheel conveyor 2 when the work is carried in.

When the work W is carried in to the predetermined carry-in position in this way, the vertical movement cylinder 31 of the first work positioning stopper 3 is actuated and the work contact member 32 is brought into contact therewith.
Is moved to the protruding position above the wheel conveyor 2. Next, the rear end edge of the work W is brought into contact with the work contact body 32, and the front end of the work W is placed on the fixed mold 15 and the rotating roller 18, and in this state, the first work holding device 21 Of the vertical movement cylinder 22 and the vacuum pad 23 are actuated, and each vacuum pad 23 sucks and holds the lower surface of the work W,
This prevents the work W from being displaced. In this state, the holding cylinder 8 is operated to lower the holding die 13, and the work W is fixed by being sandwiched between the holding die 13 and the fixed die 15 (solid line position in FIG. 5). At the lower limit position of the pressing die 13, the roller follower 9 at the tip of the plate pressing beam 7 is fitted into the U-shaped groove 10a of the guide plate 10 as shown in FIG. The roller follower 9 advances by the operation of the clamp cylinder 11, and the wedge surface 12 of the plate pressing beam clamp 12 moves forward.
It is pressed downward by a and positioned.

When the work W is set at the predetermined position in this way, the holding of the work W by the first work holding device 21 is released, and then the bending cylinder 20 is operated to move the bending beam 16 upward about the bending center 13b. When it is rocked to, the rotary roller 18 moves the work W upward while also rolling the work W up to a predetermined position (the position indicated by the chain double-dashed line in FIG. 5) about the bending center 13b, whereby the work W is held by the pressing mold 13. It is pressed by the bending surface 13a and bent at a bending radius R. At this time, the work W is bent by a predetermined angle more than the bending angle in consideration of the springback amount. And
When the bending up to a predetermined angle is completed, the bending cylinder 2
By operating 0 in the reverse direction, the rotary roller 18 is returned to the position shown by the solid line in FIG. 5, and one bending process is completed.

In the case where the bending product to be obtained has a closing shape with a closed cross section, when the bending work on one side is completed, the work W is once moved forward (to the left in FIG. 5) and then the first work is performed. Workpiece positioning stopper 3 of servo motor 3
Driven by 5 to move forward to a predetermined position, work W again
Is brought into contact with the work contact body 32 of the first work positioning stopper 3 to bend the next side. Thus
Bending up to the side immediately before the last side can be performed by the same process. Note that each of these steps is the same as the steps shown in FIGS. 11A to 11C shown as a conventional example.

The procedure of bending the final side will be described below with reference to FIG. At the time of bending the final side, the work W is changed in direction by 180 °, and the front end edge of the work W is brought into contact with the second work positioning stopper 4 to be positioned, and the bending is performed in the same manner as in the above-described steps. 1 Work holding device 2
The lower surface of the work W is sucked and held by each of the vacuum pads 23 of No. 1, and the work W is held between the die 13 and the fixed die 15 and fixed.

After this, as shown in FIG.
The work holding device 25 is attached to the vertical movement cylinder 26 (see FIG. 2).
Is lowered to the lower limit position, and the upper side W _{1 of the} work W that has already been bent by the vacuum pad 27 and is bent downward by θ ₁ by its own weight is suction-held. Next, as shown in (b), the vacuum pad 27 is raised to a preset work holding position. Here, the work holding position is set to a predetermined position such that the angle ∠B of the corner B of the work W becomes 90 ° + θ ₂ and the work W is lifted within its elastic limit.

Next, in the state where the upper side W _{1 of the} work W is held by the vacuum pad 27 as described above, the work W by the first work holding device 21 as shown in (c).
After releasing the holding, the bending cylinder 20 is operated to bend the final side W _{2 in} the same manner as the above-described bending process. Also in the bending process at this time, the work W is bent until the angle ∠D of the corner D becomes 90 ° −θ _{3 in} consideration of the springback amount. In this case, since the upper side W ₁ is lifted by the vacuum pad 27, a clearance m is formed between the lower end of the side W ₃ which is first bent and the upper end of the final side W ₂ , and these sides W ₁ are bent. The side W ₃ and the final side W ₂ do not interfere with each other.

Then, when the bending cylinder 20 is returned to the original position, the final side W ₂ returns to the position where ∠D becomes 90 ° as shown in (d), and in this state, the state changes to (e). Upper side W ₁ with vacuum pad 27 as shown
By releasing the holding, the clearance (opening amount) n of the abutting surface between the side W ₃ and the final side W ₂ becomes almost zero, and the final bent product is completed.

According to this embodiment, when bending a cylindrical body having a polygonal closed cross-sectional shape (closing shape),
Since the mouth opening of the butt surfaces can be made almost zero, it is possible to save the trouble of re-forming processing in the later process or dividing the work into two and welding them later, and the inside of the machine during bending. It is possible to prevent the occurrence of an accident due to the operator putting his hand in and lifting the work, and the bending can be performed easily and accurately. Further, since the mouth opening amount of the abutting surface can be made almost zero, automatic welding of the abutting surface becomes possible.

Further, in the bending machine of the present embodiment, since the rotating roller 18 is pressed onto the work W for bending, the work W is not scratched.

In the above embodiment, the first work holding device 21 and the second work holding means 25 are used to hold the work W by using the vacuum pads 23 and 27, respectively. Instead of these vacuum pads, an electromagnetic magnet is used. Can also be used.

In the above embodiment, the first work positioning stopper 3 and the second work positioning stopper 4 are also provided.
However, the workpiece positioning stoppers may be manually operated. Further, the loading of the work W and the pressing of the work W against each work positioning stopper may be performed automatically or may be performed manually.

Further, in the present embodiment, the closing bending of the quadrangular section has been described, but it goes without saying that the present invention can be applied to the closing bending of other polygonal sections. Further, by increasing the number of sides of this polygon by a considerable amount, it is possible to perform closing bending of a circular cross section.

Further, as the driving method of the bending beam 16 which supports the rotating roller 18, instead of performing the swinging motion around one point as in the above embodiment, 2
It is also possible to perform the oscillating movement by circularly interpolating using an NC drive device of axis control.

[0043]

Since the present invention is configured as described above, when bending a cylindrical body having a polygonal closed cross-sectional shape (closing shape), it is not affected by the bending of the work, Further, it is possible to perform the closing bending easily and accurately without scratching the work and avoiding the danger to the operator.

[Brief description of drawings]

FIG. 1 is a side view showing an entire configuration of a bending machine according to an embodiment of the present invention.

FIG. 2 is a front view of a bending mechanism portion according to an embodiment of the present invention.

FIG. 3 is a side view of the plate pressing beam clamp portion according to the embodiment of the present invention.

FIG. 4 is a side view of the first work positioning stopper according to the embodiment of the present invention.

FIG. 5 is a partially enlarged side view of a bending mechanism portion according to an embodiment of the present invention.

FIG. 6 is an explanatory view of a bending process of the final side in the embodiment of the present invention.

FIG. 7 is a perspective view of a bending product having a closing shape.

FIG. 8 is a diagram showing a first example of a conventional processing method for obtaining a bending product having a closing shape.

FIG. 9 is a diagram showing a second example of a conventional processing method for obtaining a bending product having a closing shape.

FIG. 10 is a diagram showing a third example of a conventional processing method for obtaining a bending product having a closing shape.

FIG. 11 is an explanatory view of a processing process for obtaining a bending product having a closing shape by using a bending machine.

FIG. 12 is an explanatory view showing a state in which sides interfere with each other in a conventional bending process.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Bending mechanism part 3 1st workpiece positioning stopper 4 2nd workpiece positioning stopper 5 Stand 13 Holding die 13a Bending surface 13b Bending center 15 Fixed die 16 Bending beam 18 Rotating roller 20 Bending cylinder 21 First work holding device 25 Second work holding device W Work W ₁ Upper side W ₂ Last side W ₃ Side

Claims (4)

[Claims] 1. A fixed die fixed on a pedestal,
(B) A holding die which has a bending surface formed of an arcuate surface with a predetermined radius on one side and which can move up and down to sandwich a plate-like work with the fixed die, (c) a bending center of the bending surface A bending beam that is swingably supported on the gantry about a point on the line of movement, and (d) is rotatably supported by the bending beam, and moves around the bending center as the bending beam swings. By doing so, a rotary roller that is pressed onto the work sandwiched between the fixed mold and the pressing mold, and (e) a plurality of bending-worked products of the work to obtain a closing-shaped bent product having a closed cross section. At this time, the bending machine is provided with a work holding means for holding and raising the already bent side at the time of bending the final side to prevent interference between the sides. 2. The work is held until the bending beam starts an oscillating operation after the work is sandwiched between the fixed mold and the pressing mold to prevent displacement of the work. 2. A misalignment prevention means for preventing the displacement is provided.
Bending machine described in. 3. The bending machine according to claim 1, further comprising a positioning stopper that abuts against an end edge of the work when the work is bent to define a bending leg length of the work. 4. The bending machine according to claim 3, wherein the positioning stoppers are provided in front of and behind the work carrying-in direction.